stevenf

Beginning to gather parts for my 86 pickup to do a 4.3 swap. Ive read that the tbi is often preferred for ease of wiring. However, I found a donor 95 blazer with low miles and its complete. Ive read that the cpi is more complicating to wire up. Being that I have never wired a vehicle it seems a bit intimidating.
Trying to get an idea on the extent of the engine swap I want to list my run down and see if im missing something.

Pulling engine, harness and ecu from the donor. Mounting motor harness and ecu in truck using toyota 5sp trans.
For temperature I have to get an adapter.
For oil pressure I get an adapter.
Speedo is mechanical to trans.
Only thing left is to wire tach and ignition. Here is where I would have to trace down the wiring diagrams for both vehicles. Find the ignition and power wires to splice together. Find the tachometer wires and splice into the new harness for the distributor. Then ill use the diagnostic plug and run new wires to connect to engine harness.
Next would be splicing new harness to ignition/fuel pump . Am I missing anything?

james92toy

I have a 94 4.3 cpi , with stock l460e transmission a 92 4runner , smog legal in ca. I love my 4.3 swap . Lots of power , easy to work on. Gas milage not so good . 12 mpg city 16 hwy.
This is my first auto trans wheeling and i would never go back to stick.
Everything works like stock in my truck and looks like it came from the factory with a 4.3.

Are you trying to be smog legal ?
The cpi's mostly came with automatics so a stick might make it harder to smog cause you would have to get the computer ref lashed .

1992 to 1995 1/2 cpi's have a sliver computer under the dash. These are obi 1
smog. Also you can tell because the distributor wires will point up vertically. Less wiring . Its what all after market places sell harness for. This is the one you want.

After 1995 1/2 they went to obd2. more wires. Couple more sensors.
They have a black computer on pass fender , distributor wires point up horizontally .

You can make a 1995 1/2 into an obd1 by swapping out distributor , computer and harness , the motor is the same.

A tbi 4.3 is about 160 hp.
A cpi 4.3 is 195 hp , better heads and cam.

Wiring.
You could go through stock harness and cut out what you don't need , like wires that go to auto transmission.
I went with a "painless harness" about $400. Very simple to hook up.
You need a factory toyota wiring manual "get one from ebay about $30"
and one for your 4.3.
You will splice into your body harness to hook up gauges, very easy.

Temp sensor : buy a stock toy , drill and tap into intake water jacket , wire to body harness .
Oil sensor : cpi computer needs its own , put a tee fitting then screw a toyota in and wire to body harness
Tach : Wire from back of distributor to body harness .
Fuel pump : Wire comes from computer to pump .
DONT THROW AWAY ANYTHING TILL YOUR DONE WITH SWAP.
Here's some pic's

stevenf

Wow thanks for the quick response and great info! I was going today to pull a 95 1/2. Im glad you told me so now i can swap distributors,ecu, and harness from another year. The 95 1/2 has 135k miles with everything else over 200k!
Your motor looks amazing in that truck! Very nice attention to detail!
Did you use stock exhaust manifolds? What adapter kit did you use for the tcase?

Also, if i get the harness from an automatic. Is it simply just a matter of removing the trans wires? Can vss be removed for a manual trans?

james92toy

Thanks for the complement , took me along time to build cause I did entire truck before driving it .

Yes stock exhaust manifolds . The y. Pipe connects real close to frame .

Advanced adaptors For adapters .
Buy adaptors from a dealer it will be cheaper than their web site .
I was told their motor mounts suck .

I think you can cut out wires you don't need but your computor will be looking for the vss so it needs to be reflashed .

Also get 4.3 fuel pump and bracket from inside tank, you wil need to put this in yours.
Or buy inline pump for $50 to $100 . Pump is hi pressure about 65 psi , stock toy I think is about 30 psi.

Can you weld and fabricate ?
Do you have the gm truck where you are doing the swap ?

stevenf

I have some 1/4" mounts from an unknown company that i plan to use. Yes i can fabricate and weld. The only thing that worries me is wiribg only because i have never done it. It seems simple enough just time consuming.
Is the only one ecu? I will need all plugs for ecu as well as the engine harness. The cut plugs will allow me to splice everything else in.

james92toy

Yes 1 ecu. Engine harness plugs into ecu .
Ecu needs

There is one other small one that's about the size of a pack of cigarets , that's for the vss signal.

Key on off power
Ground
Fuel pump wire
Wire from brake switch (might not need this if your not going with auto trans)

Take your Toyota engine harness off . Unplug it from body harness at passenger side kick panel . Cut the engine harness about 6 " from plug . This is where you will be wiring tach , oil ,temp , ecu power to and then plug it back into body harness. Kinda scared me at first , once I figured it out it was easy .

stevenf

What radiator are you running? Was anything else needed from the donor like ignitor/coil box?

Numbchux

I have a '92 CPFI 4.3 swap. And I did the wiring for a friend's '93 CPFI 4.3 into a CJ5. Mine has the 4L60 trans behind it, his had a manual transmission (and almost no working gauges....someday he'll re-do the dash).

I have wired in a USB cable into mine, and installed TunerPro RT onto my lap top so I can read and log parameters and look for/diagnose issues.

I've done wiring for literally dozens of engine swaps. Mostly subaru engines, but a few other things. The CPFI was one of the easiest, very nicely laid out, unplug the harness from the body, and you really don't have much extra. I got an OEM wiring diagram book on ebay for the '92 Blazer, and found some decent wiring diagrams in my Haynes manual for the toyota (this left some to be desired since mine is a turbo with an automatic and digital gauges, but you probably won't have this issue). The GM book was completely accurate for what we needed for the '93 swap into the Jeep (there were some extra wires in the harness for the transmission, but everything we needed was covered).



My 22RTE and the 4.3 both use 2 temp sensors. One for the engine, and one for the gauge. The gauge sensors are interchangeable. I put the 22RTE one in the 4.3 block (passenger side, between exhaust ports).

*technically* the GM oil pressure sensor is not for the ECU. It gives power directly to the fuel pump. The ECU does NOT supply power to the fuel pump, but it does read it. The ECU turns on the fuel pump relay to prime the system, but when the engine is running, it is oil pressure that powers the pump while the engine is running. The oil pressure sensor is both a on/off switch, that powers the fuel pump as I mentioned, and it has one wire that supplies calibrated resistance to ground for the gauge. As far as I could tell, the resistance was considerably different than what Toyota uses. Luckily, both companies use standard pipe thread for their sensors. So some hardware from the plumbing section at Menards left this:


Now, I had the fuel pump relay begin to fail on the trial (I had other issues too, ended up being the optical sensor in the disty), when I plugged my laptop in, I was only getting 9v for the fuel pump when priming, and then it jumped to battery voltage once oil pressure came up. I wired the pump to one of my un-used auxiliary light circuits that I added with the swap. I have left it this way for now....may or may not wire it back.


Tach. I have a signal converter to convert the 6-cyl signal to 4-cyl. I have used this on Subaru analog gauges before, doesn't work with my digital tach. So I have an aftermarket tach...It's possible a 6-cyl OEM tach would read correctly directly from the signal wire on the 4.3 coil.

I have the blazer fuel pump mounted to the toyota bracket in my tank. Took a few minutes with the dremel to modify it to accept the GM strainer....but it worked fine.



James92toy is dead on, "Take your Toyota engine harness off . Unplug it from body harness at passenger side kick panel . Cut the engine harness about 6 " from plug . This is where you will be wiring tach , oil ,temp , ecu power to and then plug it back into body harness. Kinda scared me at first , once I figured it out it was easy."

I pulled it all in-tact, and found the wires I would need (having the plugs at the engine made it easier to identify the correct wire) before cutting back the un-needed. Then spliced into the GM harness where needed. So it is plug-and-play just like stock.


I had to do some wiring diagram-studying, and note-taking to track down all the power wires. There are a couple switched and un-switched, but everything else was pretty simple.




I simply hooked up the VSS sensor from my toyota speedometer to the GM ECU. When I hooked up my laptop, I found out that the ECU thinks I'm going twice as fast as the gauge does, as far as I can tell, the overdrive operation is the only thing effected. Jagsthatrun.com offers a speed sensor that can be attached in-line with the toyota cable at the tcase, I will probably use one of these.


My friend's Jeep, we just omitted all transmission-related wiring. No VSS, etc. It seems to run fine (it's not street driven, so it might not be perfect, but it gets around). It does not have a CEL hooked up either, so I'm sure it's tripping codes...



Pics:
CJ5





Mine:

james92toy

Im running a stock toyota 3.0 v6 radiator with home made fan shroud . Never had any cooling issues .

Good tech Numbchux. Thanks. Can you tune your motor for better mileage or adjust shift points for transmission with the lap top ? Thats exactly the way i did my oil pressure
Tee .

stevenf

Where can this usb setup be purchased? Id like to read more about it. I only want it for engine diagnostics. Is it easier to install than the typical connector would be?
Also, the engine im looking at is in a 95 blazer with under hood ecu. I plan to pull a distributor from a pre 95. Willnthe 95 wiring harness be my only option?

stevenf

Also did you increase fuel line size or stick with stock yota?

james92toy

I don't remember size exactly but i could look. I kept stock toy fuel line out of tank and long frame till about the crossmember then i flared the end connected with a brass pushloc fitting to a 3/8 pushloc fuel hose then a fliter then to motor . Summit racing sells gm efi fittings that will go to your intake fuel hookup .
I made my own fittings from the gm aluminum hose but I'm going to swap them to summit.

I think 3/8 pressure and 5/16 return

This will be your question .

Power steering : Cut the flare ends off both gm and toy hoses where they screw into the box. Put the toyota ends on the gm hoses and re flare the ends with a double flare tool. If you don't have a double flare tool go buy a good one so you can make fuel lines and brake lines also.

stevenf

One the swap with the 5sp, did you keep the stock yota clutch m/c?

stevenf

Also, what can I get rid of on this engine to make it simpler? Any emissions, sensors that will be unecessary in the toyota?

stevenf

Dont bail on me now please lol! This thread is a good article for future swap searches! For the 5sp, the AA bellhousing requires 168t flywheel and high torque starter. What starter are yall running?

james92toy

None needs all of them to run good. But if your running a 1995 +obd2 motor and using obd1 wiring.There is a crank shaft sensor in the timing chain cover you don't need. Replace it with a earlier cover that don't have it or just leave it and not hook anything to it. Also a good thing to check on these motors is the spider injector and the 2 short hoses under the top cover. Sometimes they will start to leak. Look for gas stains in the pockets around the injector. I thought i read gm has an up grade for it.




This is what i fab ed up for a 69 camaro shifter

stevenf

That shifter is crazy cool! I really appreciate all the help! This thread will make a good resource for future searches. I plan to start the swap monday so yall do me a favor and check back often. I have a feeling I wil have alot more questions soon.
Last one for a few days, what starter are you running with the 5sp?

Numbchux

Yep, I'm using the 22RTE radiator with an electric fan and no shroud. Haven't had any issues.

It is theoretically possible to tune via this cable/program. But as far as I understand, it requires putting a new ROM chip in the ECU that can be reprogrammed. I don't really have any desire to do that, so I haven't looked into it.

And, being a '92, my 4L60 is not a 4L60E, only thing electronically controlled is the torque converter

I got this usb plug http://www.aldlcable.com/sc/details.asp?item=aldlbareu

It's 2 wires, if you don't have the ALDL plug, it's still crazy easy to find the 2 wires in the harness and splice in permanently. IIRC it's a signal wire and a ground.

I'm running 3/8s rubber Fuel Injection hose for both feed and return the whole length for simplicity. Stock would be fine (basically 3/8 feed and 5/16 return. Toyota uses metrics, which are almost identical).

I'm using compression-to-hose barb adapters for all mine.

Fuel, trans cooler, and oil cooler.

My buddy's Jeep just has 3/8 hose slipped over the 3/8 steel line at the engine and clamped. Doesn't leak a drop...



My initial plan for the power steering hose was the same, but I broke one flaring tool, and the second started to do the same. So I got another Toyota line, and left the fitting on it, and cut the rubber in the middle. A local hydraulics shop crimped them together for cheap:


The OBD I engines don't have much extra. The only thing I deleted was the charcoal canister.

AFAIK, the only upgrade is for the '96+ spiders, as they are a different style.

I replaced both the large fuel lines in the intake manifold, and got a GP Sorenson reman spider injector (I work at AutoZone...) while I was at it.



I don't know the answer to your starter question. I have an Auto, and my buddy with a manual behind his 4.3 was not a Toyota trans.

I don't spend much time on the internet these days. But I'll try to keep an eye out for updates here when I'm on.


I'd recommend reading my build-up thread on here (link in my sig). It's almost all info about my swap.

stevenf

Update: i pulled the motor yesterday from a 95 blazer. The ecu was under the hood on top of passenger fender. When i got there that ecu was gone with a few wires left unplugged. Figuring i would find an ecu elsewhere, i proceeded to follow the wiring into the cab to unplug it. It was branched of into 2 more silver boxes with the biggest one looking like an ecu with two plugs,one red and one blue. I searched other 95-96 blazers and relized my 95 does not have any connectors for the under hood ecu. Although i am posituve the ecu was in the truck when i first spotted it. Why would i have 2 ecu's? There is an empty space where the one under the hood used to be but no connectors that will plug into one. My disttibutor has vertical wires.

james92toy

So is sounds like yours is obi 1 . Good. I don't remember 2 computers . My ecu has the red and blue plugs. I think the obi 2 ecu would have 4 connectors on the harness on the fender.